The present invention relates to an indicator for the grease level in rotating sleeves, especially tooth couplings, having a peripheral opening closed by a plug.
Tooth couplings filled with grease is used in great quantities in the mechanical industry. By rotation of the coupling the grease will form an annular layer on the inner side of the sleeve portion of the coupling due to centrifugal force. Because of the degree of consistency of the grease the annular layer will not substantially change its form after the machine has been stopped. For proper operation it is important that the couplings are filled with a proper amount of grease. A variation in the amount of grease is reflected in a varying thickness of the grease layer on the inner side of the sleeve-shaped portion of the coupling. On one hand, the amount of grease should not be too great. However, if the thickness of the grease layer on the other hand goes below a certain value, damages of the coupling may occur.
Since small leakages of grease from the coupling may occur under operation it is important regularly to inspect the grease level. However, experience has shown that a simple and cheap accomplishment of this inspection has been difficult. Accordingly, it is an object of the present invention to provide a simple and practical indicator for the grease level in rotating sleeves in general and especially in tooth couplings.